Ingredients:
1l water
120g dark chocolate (at least 70% cocoa solids), cut into small pieces
260g caster sugar
Method:
Add the water and sugar to a saucepan, heat gently until the sugar has dissolved then bring to a simmer. Chop the chocolate very finely and add to the simmering syrup mix. Simmer for 20 minutes, stirring frequently, until the mixture is very smooth (but make certain the mixture does not boil). Allow to cool thoroughly to room temperature then pour into the bowl of an ice cream machine and churn according to the manufacturer's instructions.
Alternatively, if you don't have an ice cream making machine, pour the mixture into a non-metallic freezer-proof dish then cover with a lid and place in the freezer. Freeze until the sorbet is almost firm (but still a little liquid). Cut the sorbet into chunks and place in a blender. Process until smooth then transfer the sorbet back into the dish and freeze again until almost firm.
Once again chop the sorbet into pieces and process until smooth. This gets rid of all the ice crystals and makes the sorbet very smooth, which is what you want. Return to the freezer-proof dish and freeze completely. To serve, allow the sorbet to soften for 5 to 10 minutes at room temperature then spoon into dessert glasses and serve, garnished with a sprig of fresh mint.